Device for sharpening hypodermic needles



April 21, 1953 F. H. sol-IN DEVICE FOR SHARPENING HYPODERMIC NEEDLES Filed Aug. 15, 1952 2 SHEETS-SHEET l INVEN TOR.

' H. SOHN ATTORNEY Aprll 21, 1953 F. H. SOHN 2,635,398

DEVICE FOR SHARPENING HYPODERMIC NEEDLES Filed Aug. l5, 1952 2 SHEETS- SHEET 2 7777777777 l WWW/7777A QM L' 63 N" 24 F/G. 6 {Mx/25T 65) i U 63 -w/ f" \`2/n 6/ 62 64 INVENTOR.

. EH. SOHN ATTORNEY Patented Apr. 21, 1953 UNITED STATES PATENT OFFICE DEVICE FOR SHARPENING HYPODERMIC NEEDLES 20 Claims.

The present invention relates to devices for sharpening tools, and more particularly to a device for holding hypodermic needles for sharpening the same.

It is well known that hypodermic needles quickly become dull. Ii used without sharpening, they are hard to insert into the tissues and flesh; and their insertion and removal are painful.

The usual practice in sharpening hypodermic needles has been for the operator to hold the needle between his or her ngers and rub the oblique cutting edges upon an abrasive stone. This method, however, has many drawbacks. If the sharpening operation is to be done properly, great skill is required of the operator. Experience indicates that this skill is ordinarily lacking in a physician or his nurse, or technician. A needle should be sharpened so that its cutting edges are positioned obliquely to its longitudinal axis and so that they lie in the same plane. Otherwise the esh or tissues will be torn during the insertion or removal of the needle. The operator has no denite means of determining that the plane of the cutting edges of the needle is in alignment with the plane of the abrasive stone. Hence, in many instances the needle is not sharpened in the proper plane, and a great deal more of the needle is ground away than is necessary. Moreover, during sharpening, the needle may be raised or lowered or rotated slightly, thus tending to round oir the cutting edges instead of providing clean sharp edges. Hence, the needle will not produce a clean cutting eiect when injected into the iiesh.

In these days, when a great many diabetics carry hypodermic needles around with them for injection of insulin, there is more than ever a need for a practical device for sharpening hypodermic needles. Needles are expensive and, if unnecessarily ground away, there is great waste.

One object of the present invention is to provide a holder for hypodermic needles for use in conjunction with a hone, or other abrasive stone, which will correctly position a needle relative to the stone so that it may be properly sharpened.

Another object of the invention is to provide a holder of the character described which will enable anyone to properly sharpen a hypodermic needle without training or unusual skill. In this connection, one object of the invention is to provide a holder which will permit an individual diabetic to sharpen his own needles.

Further objects of the invention are to provide a holder for sharpening hypodermic needles which is simple in construction, has no parts to get out of order, requires a minimum of adjustment and skill in use, and is relatively inexpensive.

Other objects of the invention will be apparent hereinafter from the specication and from the recital of the appended claims.

In the drawings:

Fig. 1 is a side elevation of a needle holder constructed according to one embodiment of this invention, showing a hypodermic needle mounted therein for sharpening, and showing the needle engaged with the sharpening stone;

Fig. 2 is a plan View of the device;

Fig. 3 is an end view of the device, taken as indicated on the line 3-3 of Fig. 1, looking in the direction of the arrows;

Fig. 4 is a view similar to Fig. 1 showing a modified construction;

Fig. 5 is a view, similar to Figs. 1 and 4, showing a still further modication of the invention;

Fig. 6 is a section on the line 6 6 of Fig. 5, looking in the direction of the arrows;

Figs. '7 and 8 are fragmentary side views illustrating the operation of the clamp which forms a backing member for the needle holder in this embodiment of the invention;

Fig. 9 is a view similar to Fig. 5, showing the position of the needle holder when it is freed to float; and

Fig. 10 is a fragmentary section of the parts in the position shown in Fig. 8, and similar to the section of Fig. 5.

Referring now to the drawings by numerals of reference, and first to the embodiment of the invention shown in Figs. 1 to 3 inclusive, 26 denotes a base or block for carrying the needle and the parts which support and hold the same. The block 20 has a longitudinal groove 2l in one side which has parallel, plane side walls, and a plane bottom. Adjustably mounted on the block 20 to slide in the groove 2l is a holder 22 which is of general L-shape. This holder seats against one side face of block 20 and has a projecting portion or leg 23 that has plane parallel sides and that engages in the groove 2l.

The block 20 is provided with a plurality of equi-spaced holes 25; and the holder 22 is provided with an elongate slot 25. A knurl-headed screw 21, whose shank is adapted to pass through the slot 26 of holder 22, and which is adapted to thread into any selected one of the holes 25 in the block 20, is provided to secure holder 22 in any adjusted position longitudinally on the block 2U.

A tapered arbor 24 is secured in the holder 22 with a pressed fit. Every hypodermic needle N is provided at one end with a tapered bore to receive the syringe. The arbor 24 is made to the same taper as the syringe arbor so that a needle N, which is to be sharpened, can readily be pushed onto the arbor 24 and will be securely held there. The slot 2| is made of a size to snugly receive the hexagonal gripping portion 33 of the needle so that the needle, when mounted on arbor 24, will be held against rotation in the slot 2|. It is an easy matter, therefore, to position the needle in the device of the present invention so that its cutting edge will be in the proper plane for sharpening.

Mounted in the slot 2| to have a pressed fit therein is a guide 3G. This guide has a hole 32 through it through which the shank 3| of the needle N, which is to be sharpened, can be passed. The guide block serves not only yas a means for supporting the needle, but also as a means for straightening the needle, for as the shank 3| of the needle is passed through hole 32 it will be straightened if it is bent.

Mounted upon the block 20 is a slide 35 that forms a backing or seat for the needle adjacent the point of the needle. This slide is adjustable transversely of the block 2B and is secured in any adjusted position by a knurl-headed locking screw 36 which passes through an elongate slot 31 in the block and threads into the slide 35.

The backing slide 35 has a bottom face, a portion 38 of which is parallel to the axis of the needle, and another portion 39 of which is inclined to the portion 38 at an angle corresponding to the angle which it is desired to sharpen on the needle. The tubular needle N seats against portion 38 of slide `35.

The bottom face 40 of the block 25 is inclined to the longitudinal center line of slot 2|, that is, to the longitudinal axis of needle N, at an angle equal to the angle which it is desired to sharpen on the end face of the needle.

To use the device, the needle, which is to be sharpened, is mounted upon the arbor 24 of the holder 22, with its shank 3| passing through the hole 32 in the guide 3.0, and with the end face 42, which is to be sharpened, in a plane parallel to the plane of the active surface 44 of the abrasive stone 45 that is to be used in sharpening the needle; and the holder 22 is adjusted in the slot 2| to a position where the surface 42 of the needle projects enough beyond the bottom face 4G of the block 20 to permit taking off the desired amount f stock in sharpening. Then the holder 22 is secured in its adjusted position by threading up on the locking screw 2l. Then the backing slide 35 is adjusted so that the needle is supported adjacent its point a-nd will not bend or deliect in the grinding operation. Then the operator grasps the device, holding the surface 42 of the needle against the plane face 44 of the abrasive stone 45, and moves the block 20 back and forth across the stone. In this movement, the surface 40 of the block riding upon the plane surface M of the stone guides the needle in its sharpening motion. Thus, the needle will be ground to the desired angle.

In order to assist the operator in holding the block firmly diuing the grinding operation, a

groove 46 may be provided in the upper face of A the block, as shown in Fig. 3. The operator can place his index linger in this groove, While grasping the block at opposite sides with his thumb and other fingers, respectively. The guide surfaces 39 and 40 for the needle straddle the needle,

insuring accurate positioning of the needle for sharpening.

Of course, in time, the surface 40 will be worn down, but this is a hardened surface to begin with and will wear much less slowly than the needle, so that many needles can be sharpened before the device is worn away. The slide 35 can be adjusted to compensate for wear of the surface 3Q.

The needles used by diabetics for insulin injection are much shorter than those used by physicians and in hospitals for injections. Hence a device can be made in a pocket size according to this invention for use by diabetics in sharpening their needles. Such a device is illustrated in Fig. 4. It is a miniature of the device shown in Figs. l to 3 except that the guide 3U is omitted since the shank of the insulin-injecting needle is so short that the guide is not needed. Otherwise, the device of Fig. 4 is like that of Figs. l to 3, and the saine reference numerals are used in Fig. l to designate the like parts of the device of Figs. l to 3 except that the reference numerals in Fig. 4 are primed.

With the constructions illustrated in Figs. l to 4 inclusive the needle is held firmly against the hone. In many cases, it may be desirable to have the needle pressed resiliently against the grinding stone. For this purpose, the modified construction cf holder shown in Figs. 5 to 10 inclusive may be employed. Here the supporting block, the backing slide, and the guide may be identical with those previously described. Like parts are indicated in Figs. 5 to 10 inclusive by the same reference numerals as employed in Figs. 1 to 3 inclusive.

The principal difference between the construction of Figs. 5 to l0 inclusive and that of Figs. l to 3 inclusive is in the holder. In Figs. 5 to l0 inclusive, the holder is denoted at 52. It is L-shaped, as before, and has one leg engaging in the slot 2|" cf the block 20". This slot, as before, is of a width to fit closely to the hexagonal portion 33" of the shank of the needle. It carries an arbor 24", similar to that previously described, on which the needle is mounted. It has a slot 26 in it; and it is adapted to be secured in any adjusted position by a knurl-headed screw 2l" which may be threaded into any of the holes 25" of block 20". It diiiers from the holder 22 previously described, however, in that it is hollowed out, as denoted at 53 (Fig. 6), to receive the head of a spring-pressed plunger 54. This plunger is guided in bore 53 by a bushing 55. It is constantly urged outwardly of the bore 53 by a coil spring 51 which is interposed, between the inner end of the plunger and the opposed bottom face of the bore.

A locking member 653 is provided to cooperate with the holder 52. This locking member comprises a block 5| in which is XBdly SC1l1`0d a fine screw threaded shaft 62. Mounted upon this shaft and in threaded engagement therewith is a lever arm G3. The block 5| is adapted to be insei-ted in the slot 2| of the supporting base 20" with the block 6| seated against one plane side 64 (Figs. 7 and 8) of slot 2|". When the lever 83 is swung inwardly about the shaft 62, from the position of Fig. '7 to that of Fig. 8, it threads on that shaft a sufficient distance to abut against the side 65 of the slot 2|, and to lock the blocl; 6| in the slot. When the lever 63 is swung outwardly to the position of Fig. 7, it threads on shaft 62 a sufficient distance to clear the side 65 of the slot, as shown exaggeratedly in Fig. '7.

This releases the clamping block. The block 6I is cut away, as denoted at 66 (Fig. 6) to permit free outward swinging movement of the lever.

The needle is adapted to be passed, as in the iirst described embodiment or" the invention, through a hole in a guide block 30" which is secured in slot 2l"; and it is adapted to be backed up by a backing slide 35". The backing slide is slidable transversely of block 20 and is adapted to be secured in position by a knurled nut which passes through a slot 37" in block 35 and threads into the backing slide. The backing slide may be identical with that previously described.

In use, the needle, which is to be sharpened, is mounted upon the arbor 24 with its shank passing through the hole in block 3Q", the holder 52 is secured on the block 20 in the same general way as described in reference to the block 22, namely, it is adjusted along the block 20 until the needle N extends into a position to be engaged by the stone. Then the backing slide 35" is adjusted so that the needle is supported adjacent its point. The locking member EB is then shoved into and along the slot 2|" until it abuts against the holder 52. Then the lever 63 is swung downwardly to lock the locking member in position. Then the screw 21 is released, allowing the holder 52 to float in the slot 2i. The release of the screw 21" causes the spring plunger Sil, by its abutment against the face El' (Fig. of the locking member @il to move to the left, holding the needle resiliently against the sharpening stone.

The spring pressure forces the needle to position shown in Fig. 9, tending to hold it in that position under spring load. The spring 5l is selected to apply about a four pound spring pressure. This is sufficient to hold the needle N in engagement with the surface 44" of the stone l5 and to insure that as the block 20 is moved back and forth across the stone with its surface 40 riding on the surface 114 of the stone, the proper amount of stock will be removed from the needle to sharpen the needle.

In all embodiments of my invention the cutting edges will be ground on the needle in the proper plane, thereby insuring that a minimum length of the needle will be removed in a sharpening; in successive sharpenings a needle will be sharpened in parallel planes, thereby insuring maximum life of the needle; the needle is positively backed up during sharpening; the backing slide is adjustable so that various diameters 01": needles can be sharpened in the one holder; the holder is adjustable so that different lengths of needles can be sharpened; bent needles are straightened in the act of mounting them in the device; and the sharpening operation itself is effected with a pressure feed.

While the invention has been described in connection with several different embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, and adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. A device for use in sharpening hypodermic needles 0n an abrasive member, comprising `a supporting block adapted to be reciprocated over the face of said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide the holder in its adjustment, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, said block having a bottom face slidable over said abrasive member and inclined to the longitudinal center line of said slot at an angle equal to the angle at which it is desired to sharpen the cutting edges of a needle, and a backing slide movable transversely oi said block to back up the needle behind and adjacent its point.

2. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide the holder in its adjustment, an arbor secured to the holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, said block having a bottom face slidable over said abrasive member and inclined to the longitudinal center line of said slot at the angle at which it is desired to sharpen the cutting edges of a needle, means for clamping the holder in any adjusted position, and a backing member adjustable transversely of said block to back up the needle behind and adjacent its point.

3. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide the holder in its adjustment, an arbor secured to the holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, said block having a bottom face slidable over said abrasive member and inclined to the longitudinal center line of said slot at the angle at which it is desired to sharpen the cutting edges of a needle, means for clamping the holder in any adjusted position, and a backing member adjustable transversely of said block to back up the needle behind and adjacent its point, said backing member having a bottom surface adapted to extend longitudinally beyond the point of the needle when the needle is in sharpening position and inclined to the longitudinal center line of said slot at the angle at which it is desired to sharpen the cutting edges of the needle and adapted to engage the abrasive member whereby said device contacts the abrasive member at opposite sides of the point of the needle.

4. A device for use in sharpening hypodermic `needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, a needle holder adjustable longitudinally on said block. an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of adjustment of said block, and means for holding the needle against rotation during such adjustment, said block having a bottom face slidable over said abrasive member and inclined to the direction of adjustment of the holder at the angle at which it is desired to sharpen the cutting edges of the needle.

5. A device for use in sharpening hypodermio needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, a needle holder adjustable longitudinally on said block, an arbor secured to said holder and on Which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of adjustment of said block, means for holding the needle against rotation during such adjustment, and a backing member adjustable transversely of said block to back up the needle behind and adjacent its point, said block having a bottom face slidable over said abrasive member and inclined to the direction of adjustment of the holder at the angle at which it is desired to sharpen the cutting edges of the needle.

G. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, a needle holder adjustable longitudinally on said block., an arbor secured to said holder and on 'which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of adjustment of said block, means for holding the needle against rotation during such adjustment, and a backing member adjustable transversely of said block to back up the needle behind and adjacent its point, said block having a bottom face slidable over said abrasive mem er and inolined to the direction of adjustment of the holder at the angle at which it is desired to sharpen the cutting edges of the needle, and said backing member having a bottom surface adapted to extend longitudinally beyond the point of the needle when the needle is in sharpening position and inclined to the direction of adjustment of said holder at the angle at which it is desired to sharpen the cutting edges of the needle and adapted to engage the abrasive member whereby said device contacts the abrasive member at opposite sides of the point of the needle.

7. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciproca-ted over the face of said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide the holder in its adjustment, an arbor secured to said holder and on which the needle, vhich is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, means for holding the needle against rotation during such adjustment, said block having a bottom face slidable over said abrasive member and inclined to the direction of adjustment of the holder at the angle at which it is desired to sharpen the cutting edges of the needle.

8. A device for use in sharpening hypodermio needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide said holder in its adjustment, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, said slot being shaped to engage said needle and to hold said needle against rotation during adjustment of said holder, and said block having a bottom face slidable over said abrasive membel` and inclined to the direction of adjustment of the holder at the angle at which it is desired to sharpen the cutting edges of the needle.

9. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face 0f said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide said holder in its adjustment, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted With its longitudinal axis extending in the direction of the longitudinal center line of said slot, said slot being shaped to engage said needle and t0 hold said needle against rotation during adjustment of said holder, and said block having a bottom face slidable over said abrasive member and inclined to the direction of adjustment of the holder at the angl-e at which it is desired to sharpen the cutting edges of the needle, and a backing member adjustable transversely of said block to back up the needle behind and adjacent its point.

il). A. device for use in sharpening a hypodermic needle that has a gripping portion which is polygonal in cross section, comprising a supporting block, said supporting block having a slot in one side face thereof that has parallel plane side faces, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide said holder in its adjustment, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, the side Walls of said slot being spaced to engage the gripping portion of the needle to hold the needle against rotation during adjustment of said holder, said block having a plane bottom face slidable over an abrasive member and inclined to the longitudinal center line of said slot at the angle at which it is desired to sharpen the cutting edges of the needle.

11. A device for use in sharpening a hypodermic needle that has a gripping portion which is polygonal in cross section, comprising a supporting block, said supporting block having a slot in one side face thereof that has parallel plane side faces, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide said holder in its adjustment, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, the side Walls of said slot being spaced to engage the gripping portion of the needle to hold the needle against rotation during adjustment of said holder, said block having a plane bottom face slidable over an abrasive member and inclined to the longitudinal center line of said slot at the angle at which it is desired to sharpen the cutting edges of the needle, and a backing member adjustable transversely of said block to back up the needle behind and adjacent its point.

12. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supportnig block adapted to be reciprocated over the face of said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide the holder in its adjustment, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, said block having a bottom face slidable over said abrasive member and inclined to the longitudinal center line of said slot at an angle equal to the angle at which it is desired to sharpen the cutting edges of a needle, and a backing slide movable transversely of said block to back up the needle behind and adjacent its point, and a guide member secured in said slot intermediate said backing slide and said arbor and having a bore through which the needle must be passed.

13. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide the holder in its adjustment, an arbor secured to the holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, said block having a bottom face slidable over said abrasive member and inclined to the longitudinal center line of said slot at the angle at which it is desired to sharpen the cutting edges of a needle, means for clamping the holder in any adjusted position, and a backing member adjustable transversely of said block to back up the needle behind and adjacent its point, and a guide member secured in said slot intermediate said backing slide and said arbor and having a bore through which the needle must be passed.

14. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, a needle holder adjustable longitudinally on said block, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of adjustment of said block, means for holding the needle against rotation during such adjustment, a backing member adjustable transversely of said biock to back up the needle behind and adjacent its point, and a guide member secured to said block between said backing member and said arbor and having a bore through which the needle must be passed, said block having a bottom face slidable over said abrasive member and inclined to the direction of adjustment of the holder at the angle at Which it is desired to sharpen the cutting edges of the needle.

15. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide said holder in its adjustment, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted With its longitudinal axis extending in the direction of adjustment of said block, means for holding the needle against rotation during such adjustment, and a backing member adjustable transversely of said block to back up the needle behind and adjacent its point, said block having a bottom face slidable over said abrasive member and inclined to the direction of adjustment of the holder at the angle at Which it is desired to sharpen the cutting edges of the needle, and said backing member having a bottom surface adapted to extend longitudinally beyond the point of the needle when the needle is in sharpening position and inclined to the direction of adjustment of said holder at the angle at which it is desired to sharpen the cutting edges of the needle and adapted to engage the abrasive member whereby said device contacts the abrasive member at opposite sides of the point of the needle, and a guide member secured in said slot intermediate said backing slide and said arbor and having a bore through which the needle must be passed.

16. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of said abrasive member, said supporting block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide said holder in its adjustment, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, said slot being shaped to engage said needle and to hold said needle against rotation during adjustment of said holder, and said block having a bottom face slidable over said abrasive member and inclined to the direction of adjustment of the holder at the angle at which it is desired to sharpen the cutting edges of the needle, and a backing member adjustable transversely of said block to back up the needle behind and adjacent its point, and a guide member secured in said slot intermediate said backing slide and said arbor and having a bore through which the needle must be passed.

17. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of an abrasive member, a needle holder movable longitudinally on said block, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of movement of said holder, and means for resiliently urging said holder in one direction to hold a needle resiliently in sharpening position, said block having a bottom face slidable over said abrasive member and inclined to the direction of adjustment of the holder at the angle at which it is desired to sharpen the cutting edges of the needle.

18. A device for use in sharpening hypodermic needles on abrasive member, comprising a supporting block adapted to be reciprocated over the face of an abrasive member, said block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide the holder in its adjustment, an arbor secured to the holder and on which the needle,

which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, means for clamping said holder in any adjusted position, an abutment member adapted to be secured to said block, and resilient means interposed between said holder and said abutment member for resiliently urging said holder in one direction to hold a needle resiliently in sharpening position when the clamping means is released.

19. A device for use in sharpening hypodermic needles on an abrasive member, comprising a supporting block adapted to be reciprocated over the face of an abrasive member, said block having a slot in one side face thereof, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide the holder in its adjustment, an arbor secured to the holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot, means for clamping said holder in any adjusted position, an abutment member adapted to be secured in said slot, a spring-pressed plunger mounted in said holder to engage said abutment member to urge said holder resiliently in one direction to urge said needle resiliently to sharpening position when the clamping means is released.

20. A device for use in sharpening a hypodermic needle that has a gripping portion which is polygonal in cross section, comprising a supporting block having a slot in one side face thereof that has parallel .plane sides, a needle holder adjustable longitudinally on said block and having a portion engaging in said slot to guide said holder in its adjustment, an arbor secured to said holder and on which the needle, which is to be sharpened, is mounted with its longitudinal axis extending in the direction of the longitudinal center line of said slot and with its gripping portion engaging the side walls of said slot whereby the needle is held against rotation during adjustment of said holder, a backing member adjustable on said block transversely o1" said block to back up the needle behind and adjacent its point, a guide member secured in said slot intermediate said backing member and said arbor and having a bore through which the needle must be passed, releasable means for clamping said holder in any adjusted position on said block, an abutment member adapted to be secured in said slot against movement therein, and a spring-pressed plunger mounted in said holder to project therefrom at the opposite side thereof from said arbor and to engage said abutment member for resiliently urging said holder, when the clamping means is released, in a direction to hold the needle resiliently in sharpening position, said block having a plane bottom face slidable on an abrasive member and inclined to the direction of adjustment of said holder at the angle at which it is desired to sharpen the cutting edges of the needle.

FREDERICK H. SOHN.

No references cited. 

